985 Workbench: 2024-11-25

 Posted on 2024-11-25

My Week in Radio

  • Took down my 2M antennas to straighten and resolder.
  • Catching up the radio blog with my recent experiences.
  • Trying F4HWN firmware on Quansheng radios
    • previous firmware, AUBSUK, for my Quansheng radio was skipping channels when I activated more than 1 scan list.
    • larger display with single VFO
    • rethinking my scan lists
    • the S-meter is calibrated differently from the other firmware
  • no questions, because I should just be reading the antenna book
  • FT Challenge coming up in 2 weekends. *** Others
  • KD3ACF, JT:
    • acquired a j-pole for the attic
    • new ham with an HT
    • magmount on the car, tested with WA3VEE from Manheim High School
  • W8CRW, CR:
    • 985 activities
    • Red Rose activities
    • Salem CCARS acitvity
  • W3QP, Tim:
    • trip to HRO
    • planning trips
  • WA3VEE, Ron:
    • working on an old receiver
      • re-capping
      • Hammerland hq140x
      • terrible, loud 120hz buzz, so ordered capacitors to replace them
      • cleaned
      • fixed
      • needs just a little more work, alignment
    • got over to KC3YSM, Steve’s place to help with his antenna
      • analyzed
      • Buckmaster OCF dipole
  • KC3RFG, Jim:
    • watching 10m
    • Croatia, Belgium
    • repairing the 160m/75m dipole, new balun
  • AF3Z, Jim:
    • testing his 1-tube QRP transmitter
    • practiced some CW with a friend on 10m
    • found sweden and belgium lower in the band.
  • KC3OOK, Bill:
    • 985 net, simplex net
    • working on tower
    • helping Joe, W3GMS, assemble his new tower
  • KC3SCY, Luke:
    • lots of time off from school this week
    • 10m has been wide-open
    • spent some time on 40m SSB and AM
  • KC3VRW, Phil:
    • attempted to build a 10m inverted-V
    • MFJ tuner
    • trying tech HF frequencies

Questions

  • W3QP, Tim: Follow up on battery measurements for the TSA, Watt-hours instead of Amp-hours.
    • bigger batteries have bigger thermal events.
    • Wh is the amount of potential power.
    • Wh doesn’t require doing the math to consider voltage in combo with Ah.
    • 18Ah at 12V.
    • The nominal voltage for the cells is less.
    • Expected usable volts are even less, so Wh is less than just V*A.
    • Nominal voltage can be different across different battery chemistries.
    • Nominal voltage may not be obvious.
    • 11.1 Nominal voltage might be 12.6V at peak charge.
    • Volts and Amps are important for application, but Watt-hours is better overall for capacity.
  • AF3Z, Jim:
    • tinkering with Hartley oscillator: mica capacitors, ceramic capacitors, what’s the difference of all the different capacitors?
      • WA3KFT, John:
        • ratings: capacitance, voltage.
        • The “dry electrolytic” is a paste, not oil.
        • main purpose is filtering AC converted to DC.
        • filtering some frequencies
        • ceramic capacitors are pretty stable, until overheated.
        • mica capacitors are small capacitances, pF. used for frequency stablizing.
        • variable air capacitor
        • oil filled are higher capacitance and used for low frequencies in power supplies, etc.
      • WA3VEE, Ron:
        • film capacitors
          • different dielectric
          • used for audio.
        • paper capacitor
        • dielectric is anything that separates the plates.
        • air capacitors
      • W3QP, Tim:
        • silver mica are maybe lower loss than ceramic
        • multi-layer capacitors for higher currents
      • W3DIB, Greg:
        • negatives of certain capacitors:
          • some dielectrics leak
          • tantalums can dead-short, like in a power supply.
        • saw a cool video of people building filters for cheap radios in places with heavy RF to keep them working better.
      • WA3VEE, Ron:
        • they leak when they get overheated.
        • leads to the plate have a little resistance so generate heat.
        • capacitor can have a vent that leaks under pressure.
      • NA3CW, Chuck:
        • capacitors are deceptively complex
        • all components have some bit of capacitance, inductance, resistance.
        • vacuum dialectric for especially high voltage.
        • lots of trade-off characteristics
        • some are piezoelectric (microphone), like a condenser microphone
  • WA3VEE, Ron:
    • homework: does a capacitor allow current to flow through it? KC3SQI, Wayne:
  • solar telescope demos on December 11 at some park
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